• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.12 no.4
• /
• pp.21-26
• /
• 2016

In this study, the control strategies of indoor air temperature in floor radiant heating system were researched by computer simulation. The temperature difference based time control method using the difference of indoor set temperature and indoor temperature is compared with the existing On-Off control one for heating control performances. As a result, the temperature difference based time control method shows better thermal environmental characteristics in case of selected operational conditions in comparison with existing control one.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.681-684
• /
• 2006

Control of the temperature difference across a section is an effective way to minimize the hydration-heat-induced cracks for the structures where internal restraint is dominant. However, surface temperature may not be easily measured in situ due to the difficulty in maintaining the correct location during casting. A prediction equation for the temperature difference is proposed which can be applied without directly measuring the surface temperature if the curing condition and ambient temperature are known. Some strategies to control the temperature difference are revisited and a reasonable range of the temperature difference to minimize the crack is discussed.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2254-2255
• /
• 2008

Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products, but temperature difference between surface and center of sheet is difficult to decrease because of low thermal conductivity of ABS material. In order to decrease temperature difference between surface and center, heating profile must be expressed as exponential function form. In this study, Finite Difference Method was used to find out the coefficients of optimal heating profiles. Through investigation, the optimal results using Finite Difference Method show that temperature difference between surface and center of sheet can be remarkably minimized with satisfying Temperature of Forming Window.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.17 no.4
• /
• pp.36-45
• /
• 2021

In this study, to improve the indoor thermal environment of the radiant floor heating system, a study was conducted on the temperature change characteristics and energy consumption according to the change of the indoor air set temperature, the supply hot water temperature and the outdoor temperature. As for the control method, the on/off control and the thermal difference proportional control method proposed through previous studies were applied. In addition, in consideration of field applicability, numerical analysis was performed for the case where the indoor air temperature sensor was affected by the wall temperature. As a result, it was found that the temperature difference proportional control method is more effective for thermal comfort and energy saving than on/off control.

• Journal of Oriental Medical Thermology
• /
• v.6 no.1
• /
• pp.63-68
• /
• 2008

Purpose: We intended to researched the relations between abdominal temperature and leukorrhea. Methods: We selected the 26 leukorrhea patients and 17 control group. We measured 4 points abdominal temperature (Chung-wan(CV12), Kwan-won(CV4), Gui-rae(ST29)) by DITI. We checked the difference of temperature between CV12, CV4, ST29 of leukorrhea group and control group. And we checked the difference of temperature between CV12 and CV4 / Lt. ST29 and Rt. ST29 / CV12 and Lt. ST29 / CV12 and Rt. ST29 / CV4 and Lt. ST29 / CV4 and Rt. ST29. For statistics, we used Mann-Whitney test, SPSS 12.0 for windows. Results: The difference of temperature between CV12, CV4 and ST29 which are abdomen shows statistically insignificant result in this study. But, the difference of temperature between (${\Delta}T$) CV4 and Rt. ST29 which are abdomen shows statistically significant result. Conclusion: The leukorrhea patients show higher temperature CV12, CV4 and ST29 than control group. In lower abdomen, the temperature between leukorrhea and control group shows little difference.

• Journal of Bio-Environment Control
• /
• v.23 no.1
• /
• pp.11-18
• /
• 2014

To investigate the influence of surrounding environment on the plant temperature and examine the effect of plant temperature control by fogging and airflow, plant temperature of tomato, inside and outside air temperature and relative humidity, solar radiation and wind speed were measured and analyzed under various experimental conditions in plastic greenhouse with two-fluid fogging systems and air circulation fans. According to the analysis of plant temperature and the change of inside and outside air temperature in each condition, inside air temperature and plant temperature were significantly higher than outside air temperature in the control and shading condition. However, in the fogging condition, inside air temperature was lower or slightly higher than outside air temperature. It showed that plant temperature could be kept with the temperature similar to or lower than inside air temperature in fogging and airflow condition. To derive the relationship between surrounding environmental factor and plant temperature, we did multiple regression analysis. The optimum regression equation for the temperature difference between plant and air included solar radiation, wind speed and vapor pressure deficit and RMS error was $0.8^{\circ}C$. To investigate whether the fogging and airflow contribute to reduce high temperature stress of plant, photosynthetic rate of tomato leaf was measured under the experimental conditions. Photosynthetic rate was the highest when using both fogging and airflow, and then fogging, airflow and lastly the control. So, we could assume that fogging and airflow can make better effect of plant temperature control to reduce high temperature stress of plant which can increase photosynthetic rate. It showed that the temperature difference between plant and air was highly affected by surrounding environment. Also, we could estimate plant temperature by measuring the surrounding environment, and use it for environment control to reduce the high temperature stress of plant. In addition, by using fogging and airflow, we can decrease temperature difference between plant and air, increase photosynthetic rate, and make proper environment for plants. We could conclude that both fogging and airflow are effective to reduce the high temperature stress of plant.

• Journal of Environmental Science International
• /
• v.22 no.11
• /
• pp.1443-1449
• /
• 2013

This was an experimental study to evaluate temperature reduction and evapotranspiration of extensive green roof. Three test cells with a dimension of $1.2(W){\times}1.2(D){\times}1.0(H)$ meters were built using 4-inch concrete blocks. Ten-centimeter concrete slab was installed on top of each cell. The first cell was control cell with no green roof installed. The second and third cells were covered with medium-leaf type Zoysiagrass (Zoysia japonica) above a layer of soil. Soil thickness on the second cell was 10cm and that on the third cell was 20cm. Air temperature, relative humidity and solar irradiance were measured using AWS (automatic weather system). Temperature on top surface and ceiling of the control cell and temperature on top surface, below soil and ceiling of green roof cells was measured. Evapotranspiration of the green roof cells were measured using weight changes. Compared with temperature difference on the control cell, temperature difference was greater on green roof cells. Between two green roof cells, the temperature difference was greater on the third cell with a thicker soil layer. Temperature differences below soil and on ceilings of green roof cells were found greater than those of the control cell. Between the green roof cells, there was no difference in the temperature reduction effects below soil and on ceilings based on substrate depth. In summary, green roof was found effective in temperature reduction due to evapotranspiration and shading effect.

• Journal of Oriental Medical Thermology
• /
• v.2 no.1
• /
• pp.24-28
• /
• 2003

Purpose: We aim to research the difference of abdominal temperature in dysmenorrhea patients comparing with that of normal person. Metholds: We selected the 49 dismenorrhea patients as study group and 54 normal persons as control group, excluding the patients who have dermatitis, ared over 70 or under 10. and have extreme obesity. We compared the 4 points(Rt and Lt Gimun(LR14) and Guirae(ST29)) in thd abdomen of both group, check the temperature of those points with DITI(Dorex, DTI-16UTI) to compare the temperature difference with each other. For statistics, we use independent T-test, SPSS 8.0 for windows. Results: The temperature difference between Rt and Lt Gimun which are in upper abdomen shows statistically significant result in study group. Conclusion: The dysmenorrhea patients show larger temperature difference between Rt and Lt points in upper abdomen than normal persons. In lower abdomen, the temperature between control and study group shows little difference.

• Nuclear Engineering and Technology
• /
• v.56 no.5
• /
• pp.1698-1711
• /
• 2024

Heat pipe cooled reactors have gained attention as a potential solution for nuclear power generation in space and deep sea applications because of their simple design, scalability, safety and reliability. However, under complex operating conditions, a control strategy for variable load operation is necessary. This paper presents a two-dimensional transient characteristics analysis program for a heat pipe cooled reactor and proposes a variable load control strategy using the recuperator bypass (CSURB). The program was verified against previous studies, and steady-state and step-load operating conditions were calculated. For normal operating condition, the predicted temperature distribution with constant heat pipe temperature boundary conditions agrees well with the literature, with a maximum temperature difference of 0.4 K. With the implementation of the control strategy using the recuperator bypass (CSURB) proposed in this paper, it becomes feasible to achieve variable load operation and return the system to a steady state solely through the self-regulation of the reactor, without the need to operate the control drum. The average temperature difference of the fuel does not exceed 1 % at the four power levels of 70 %,80 %, 90 % and 100 % Full power. The output power of the turbine can match the load change process, and the temperature difference between the inlet and outlet of the turbine increases as the power decreases.

• Journal of Oriental Neuropsychiatry
• /
• v.11 no.1
• /
• pp.59-73
• /
• 2000

Depression is a psychiatric syndrom consisting of dejected mood, psychomotor retardation, insomnia and weight loss, sometimes associated with irrational guilt feeling. And it is also similiar to Hwa-byung(火病) symptom in oriental medicine. But it is difficult to diagnose with objective method. Digital Infrared Thermographic Imaging(D.I.T.I.) is one of diagnotic method that measure the changes of skin temperature in body. Specially we checked the skin temperature on depressed patients by using D.I.T.I. and compared with Bell's palsy patients and normal persons group. The results are as follows; Average body temperature of the depressed patient group is $36.68{\pm}0.43^{\circ}C.$ and that of the control group is $36.73{\pm}0.40^{\circ}C.$. So there is no meaningful difference. The depressed patient group has higher temperature than the control group by ${\triangle}T>1.0^{\circ}C$ at the following acupuncture points in these body parts - upper and lower, left and right, anterior and posterior. When acupuncture points temperature was compared superior and inferior part of the body, depressed patient group have meaningful difference at the GV-4(Myung-moon) and also in the control group. When acupuncture points temperature was compared left and right part of the body, depressed patient group have no meaningful difference and also in the control group. When acupuncture points temperature was compared in the anterior and posterior part of the body, depressed patient group have meaningful difference at the GV-4(Myung- moon) and also in the control group. From this study, we think that D.I.T.I. could be used to diagnose objectively on the depressed patients and useful to another psychoneurogenic diagnosis in oriental medicine.